# Overview
This commit makes changes to the `wiggle::from_witx` procedural in order
to allow for escaping strict and reserved Rust keywords.
Additionally, this commit introduces the ability to use a `witx_literal`
field in the `{..}` object provided as an argument to
`wiggle::from_witx`. This field allows for witx documents to be provided
as inline string literals.
Documentation comments are added to the methods of
`wiggle_generate::names::Names` struct responsible for generating
`proc_macro2::Ident` words.
## Keyword Escaping
Today, an interface that includes witx identifiers that conflict with
with Rust syntax will cause the `from_witx` macro to panic at
compilation time.
Here is a small example (adapted from
`/crates/wiggle/tests/keywords.rs`) that demonstrates this issue:
```
;; Attempts to define a module `self`, containing a trait `Self`. Both
;; of these are reserved keywords, and will thus cause a compilation
;; error.
(module $self
(@interface func (export "betchya_cant_implement_this")
)
)
```
Building off of code that (as of `master` today)
[demonstrates a strategy][esc] for escaping keywords, we introduce an
internal `escaping` module to `generate/src/config.rs` that contains
code responsible for escaping Rust keywords in a generalized manner.
[esc]: 0dd77d36f8/crates/wiggle/generate/src/names.rs (L106)
Some code related to special cases, such as accounting for
[`errno::2big`][err] while generating names for enum variants, is moved
into this module as well.
[err]: https://github.com/WebAssembly/WASI/blob/master/phases/snapshot/docs.md#-errno-enumu16
As mentioned in the document comments of this diff, we do not include
weak keywords like `'static` or `union`. Their semantics do not impact
us in the same way from a code generation perspective.
## witx_literal
First, some background. Trait names, type names, and so on use a
camel-cased naming convention. As such, `Self` is the only keyword that
can potentially conflict with these identifiers. (See the [Rust
Reference][key] for a complete list of strict, reserved, and weak
keywords.)
When writing tests, this meant that many tests had to be outlined into
separate files, as items with the name `$self` could not be defined in
the same namespace. As such, it seemed like a worthwhile feature to
implement while the above work was being developed.
The most important function to note is the `load_document` inherent
method added to `WitxConf`, and that `WitxConf` is now an enum
containing either (a) a collection of paths, identical to its current
functionality, or (b) a single string literal.
Note that a witx document given to `from_witx` using a string literal
provided to `from_witx` cannot include `use (..)` directives, per
the `witx::parse` documentation.
(See: https://docs.rs/witx/0.8.5/witx/fn.parse.html)
Two newtypes, `Paths` and `Literal`, are introduced to facilitate the
parsing of `WitxConf` values. Their public API and trait implementations
has been kept to the minimum required to satisfy compilation in order to
limit the scope of this diff. Additional surface for external consumers
can be added in follow-up commits if deemed necessary in review.
* Shuffle around the wiggle crates
This commit reorganizes the wiggle crates slightly by performing the
following transforms:
* The `crates/wiggle` crate, previously named `wiggle`, was moved to
`crates/wiggle/crates/macro` and is renamed to `wiggle-macro`.
* The `crates/wiggle/crates/runtime` crate, previously named
`wiggle-runtime`, was moved to `crates/wiggle` and is renamed to
`wiggle`.
* The new `wiggle` crate depends on `wiggle-macro` and reexports the macro.
The goal here is that consumers only deal with the `wiggle` crate
itself. No more crates depend on `wiggle-runtime` and all dependencies
are entirely on just the `wiggle` crate.
* Remove the `crates/wiggle/crates` directory
Move everything into `crates/wiggle` directly, like `wasi-common`
* Add wiggle-macro to test-all script
* Fixup a test
* wiggle: emit a metadata module containing witx document
* wiggle: put metadata module behind a wiggle_metadata feature
* wasi-common: add wiggle_metadata feature and optional witx dep
* refactor according to alex's advice
* wasi-common: make snapshots pub
* wasi-common: i do need a wiggle_metadata feature to be available
* Tweak features and such
* wiggle: fix tests by passing metadata flag to wiggle-runtime
* wiggle: need to move wiggle-runtime to a non-dev dependency
so that the feature resolves for external users of the crates
Co-authored-by: Alex Crichton <alex@alexcrichton.com>
with the prev approach, it would be passed by reference sometimes
(e.g. when used as an Array argument) but by value most of the time.
this was inconsistient.
theres no need to pass the owned version, all operations are &self.
* Impl different formatters for flags
Rather than forcing only binary formatting of flags types, how about
we implement all relevant traits (`Binary`, `Octal`, `LowerHex`, and
`UpperHex`) and allow the user to pick the most relevant one for their
use case?
Also, we use at least `Octal` and `LowerHex` in a couple of places
in `wasi-common`.
* fmt::Display for flags now inspired by bitflags
Flags is now by default formatted similarly to how
`bitflags` crate does it, namely, `dsync|append (0x11)`. In case
we're dealing with an empty set, we get `empty (0x0)`. Because of
this, any `Octal`, `LowerHex`, etc., formatters are redundant now.
Furthermore, while here, I've rewritten `EMPTY_FLAGS` and `ALL_FLAGS`
(where the former means `0x0` and the latter is the union of all possible
values) to be `const fn empty()` and `const fn all()` where the latter is
an expanded union of primitive representation values out of a macro.
This is again largely inspired by the `bitflags` crate.
* Test fmt::Display for flags
Andrew Brown
Pat Hickey
Jakub Konka
Katelyn Martin
Alex Crichton
Pat Hickey